I asked this question earlier today on Stack Overflow, however, I think it fits better here…

Background
I’m maintaining a forked repository that contains a LaTeX project. The README.md contains a .png preview of the .pdf, compiled from the example .tex file included in the repo. I often forget to update the .png version using the following ImageMagick command:

    magick convert -density 1200 -background white -alpha off Twenty-Seconds-Icons_cv.pdf -quality 90 Twenty-Seconds-Icons_cv.png

Thus I would like to automate this process using GitHub Actions.

Workflow
I think the main.yml file should look something like this, however, I don’t fully understand what I am doing.

name: PDF to PNG
on:
  push:
    branches:
      - kaspar
  pull_request:
    branches:
      - kaspar
jobs:

build:

runs-on: ubuntu-latest

steps:

- name: Install ImageMagick

run: sudo apt install imagemagick # Seems to work and already be included with ubuntu-latest...

- name: Convert PDF to PNG

run: # How?

- name: Commit the updated PNG

run: # How?

Output:

Run sudo apt install imagemagick
  sudo apt install imagemagick
  shell: /usr/bin/bash -e {0}
WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
Reading package lists...

Building dependency tree...

Reading state information...

imagemagick is already the newest version (8:6.9.10.23+dfsg-2.1ubuntu11.2).

0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Questions
It seems like this should be a pretty basic task, therefore, I would prefer to do everything from the main.yml file without creating a separate repository for this action, if possible.

1. It seems like I can just run bash shell commands with run: ; is this true?
2. How/where can I access the .pdf file in the repo from inside the GitHub Actions Ubuntu machine?
3. Where should I save the .png file, is there a ~ directory?
4. How can I commit the .png file generated by ImageMagick to the repo?
5. Would git commit <file> -m "updated png version of the CV" work?